The invention generally relates to the activation of downhole tools. More particularly, the invention relates to methods and systems used to activate downhole tools with light.
Downhole tools are typically activated by mechanical, electrical, or hydraulic means. Each of these types of actuation have potential problems. Mechanically actuated tools normally rely on translation or torsion of the tube or cable connecting the tool to the surface. However, movement on the surface does not always translate into movement down-hole at the location of the tool. Furthermore, the movement of the tool may remove it from the position where the actuation is required. Electrically actuated tools need cables in which electrical insulation is required. The insulation is often bulky and compromises the strength of the cable. Electrical actuation is also sensitive to spurious currents and interference that could result in undesirable actuation. Hydraulically actuated tools also suffer from the risk of undesirable actuation or actuation at the wrong depth. The local pressure at the tool is difficult to control in some circumstances. All the above require complex control mechanisms to prevent undesirable activation.
Moreover, reliability and safety are important when operating downhole tools, since a faulty tool can result in a substantial increase in costs and time for an operator and can also sometimes endanger the lives of workers. These issues are heightened when they relate to perforating guns, as these tools must have a very high level of reliability and safety.
Thus, there exists a continuing need for an arrangement and/or technique that addresses one or more of the problems that are stated above.